Process for applying powder to patterns.



. FRANZ DAMHORST, AUGUST KEMPER, AND ERNST UTK F'BERLIN,

' stances.

; nmrnn sirrias PATENT OFFICE.

GERMANY.

PROCESS FOR APPLYING POWDER TO PATTERNS.

" Specification of Letters Patent.

Patented March 13, 1906.

Application filed June 29,1905. $eria1No.2 67,619.

forsuch powders for patterns as consist of mineral materialsfor example,calcium carbid or quicklime or mixtures of well-known dusting materialswith such mineral sub- Such powdersfor patterns as calcium carbid andquicklime have hitherto been dusted onto the pattern in a finepulverized dry condition, in which case naturally the powder cannot beprevented from flying about in the air to a very considerable extent.-This dust constantly inhaled by the molder during the operation ofpowdering is injurious to the health on account of the nature of thepowder, so that even with regard to this oint such a dusting processmust be held to lie unsuitable for use in practice. According to thepresent process the patternpowder, particularly calcium carbid orquicklime or a mixture-of well-known dusting ma.- terials with calciumcarbid or quicklime, in a fine powdered condition, is incorporated in achemically-indifferent fluid for example, petroleumproducing a fluidmixture, and this mixture is applied to the pattern by means of asprayer in the form of a fine drizzle. The proportions of the mixtureare so selected that the liquid is thin enough to be capable of beingapplied to the pattern by means of a sprayer in the form of finedrizzle.

In the case of this process the flying about of the pattern-powder inthe form of dust is out of the question, so that the present inventionofiers in the first place an important advantage as regards health; butfor the purity of the castingthat is, for obtaining smooth surfaces onthe casting-the process requisite, as the is of great importance onaccount of the fact that the particles of fluid applied to the patternadhere better than the pattern-powder applied in a dry state, a ointwhich is particularly favorably noticea le in the case of patterns withfairly large vertical surfaces.

The action of the carbid powder or lime powder is in the case of theirapplication to the present invention exactly the same as in the case oftheir application in the dry condition-tha-t is, a separate layer of gasor steam between the pattern and mold is generated on their coming intocontact with the moist water contained in the molding-sand. Thepatternsprovided with the coating are embedded in the mold in theordinary manner. As the carbid powder or lime powder settles to thebottom if the liquid stands a fairly long time the same is to beenergetically stirred before use. The process has the additionaladvantage that no special devices for storing carbid powder or limepowder are powder is completely protected by the petroleum from theinfluenceof the air or the like.

What we claim as our invention, anddesire to secure by Letters Patent,is

1. The hereindescribed improvement in the art of treating patterns whichconsistslin rnixing with a suitable anhydrous liquid a powder capable ofgenerating a gas on contact with water and spraying the mixture on thepatterns, substantially as described.

2. The herein-described improvement in the art of treating patternswhich consists in mixing with petroleum a powder capable of generating agas on contact with water, and spraying the mixture on the patterns,substantially asdescribed. g

In testimony whereof we have signed our names to this specification inthe presence of 'two subscribing witnesses.

FRANZ DAMHORST. AUGUST KEMPER. ERNST UTKE.

Witnesses HENRY HASPER, WOLDEMAR HAUP

